The present invention relates to a novel process for the purification of water. Dissolved organic substances typically found in water supplies include man-made compounds and the natural products of plant decay, including humic acid, which can give undesirable color, taste, and odor to water. Dissolved organics also interfere with the water purification process by clogging filters and fouling resin beds. Furthermore, during treatment of the water supply at drinking water treatment facilities, natural organic matter can also react with chemical disinfectants, such as chlorine, to produce chlorinated-organic compounds, many of which are known carcinogens.
Activated carbon has long been used to adsorb organic compounds from water supplies. Typically, carbon filters are used prior to other purification processes to partially purify the water and prevent fouling of ion-exchange beds or membranes. Presently, activated carbon pre-filters are used before high performance water purification membranes, such as reverse osmosis membranes. Without a pre-filter, such membranes would rapidly clog with organic contaminants. However, all activated carbons have the disadvantage of requiring disposal or regeneration after their adsorption capacity is exhausted.
Many activated carbons, including those in powdered form, are never regenerated and remain in the residuals or sludges generated from water treatment. These residuals or sludges must then be disposed of as solid waste, usually in a landfill, which poses a secondary pollution problem.
Unlike their powdered counterparts, granular activated carbons can be regenerated using a high temperature process where the adsorbed organic materials are volatized or burned from the carbon. This process is energy intensive, and can cause secondary air and water pollution problems.